期末试题-数据库技术与应用.docVIP

北京邮电大学2007——2008学年第一学期 《数据库技术与应用》期末考试试题 考试注意事项 一、学生参加考试须带学生证或学院证明，未带者不准进入考场。学生必须按照监考教师指定座位就坐。 二、书本、参考资料、书包等与考试无关的东西一律放到考场指定位置。 三、学生不得另行携带、使用稿纸，要遵守《北京邮电大学考场规则》，有考场违纪或作弊行为者，按相应规定严肃处理。 四、学生必须将答题内容做在专用答题纸上，做在试卷、草稿纸上一律无效。 考试 课程 数据库技术与应用 考试时间 年 月 日 题号 一 二 三 四 五 六 七 八 总分 满分 20 30 10 30 10 得分 阅卷 教师 True-False Questions（20） 题号 1 2 3 4 5 6 7 8 9 10 答案 题号 11 12 13 14 15 16 17 18 19 20 答案 Multiple Choice Questions（30） 题号 1 2 3 4 5 6 7 8 9 10 答案 题号 11 12 13 14 15 16 17 18 19 20 答案 题号 21 22 23 24 25 26 27 28 29 30 答案 Fill in the Blank Questions（10） 题号 答案 1 2 3 4 5 6 7 8 9 10 Essay Questions（30） 1 2 3 4 5 Give your suggestion about this course（10） True-False Questions（1point*20） The purpose of a database is to help people keep track of things. The relational model was first proposed in 1970 by E. F. Codd at IBM. A relation is a three-dimensional table. An asterisk (*) following the SELECT verb means that all columns are to be obtained. The SQL keyword GROUP BY instructs the DBMS to group together those rows that have the same value in a column. In an E-R model, the three types of maximum cardinality are 1:1, 1:N and N:M. A null value is an attribute value that has been set to zero. A data constraint is a limitation on data values. In a relational database design, all relationships are expressed by creating a foreign key. A transaction is a group of alternative database actions from which the database can choose to perform only one of them. Two-phased locking has a growing phase and a shrinking phase. Repeatable Reads isolation is the most restrictive level of isolation. A database save is used to mark the end of a transaction. To add a NULL column to a table, we simply use the MODIFY TABLE statement. Deleting tables and relationships is basically a matter of dro